Microemulsion-based synthesis of a visible-light-responsive Si-doped TiO2 photocatalyst and its photodegradation efficiency potential

In this research, a facile microemulsion route was applied in the synthesis of a series of Si-doped TiO2 nanoparticles with uniform shape, narrow size distribution and high photocatalytic activity. The size and structure of the resulting crystals were evaluated by XRD and TEM techniques, respectively. The size of nanoparticles increased with the increment of water and calcination temperature. The photocatalytic activity of the nanoparticles was improved by decreasing the water amount in the system. In improving the crystallinity, the calcination led to the formation of quartz and anatase form of TiO2. Moreover, it was shown that the highest catalytic activity strongly depends on both the molar ratio of water-to-AOT and calcination temperature. The temperature increase resulted in the increment of crystallinity, light adsorption, and particle size. The UV-visible diffused reflectance analysis proved that the doping of the silicon ions in the TiO2 lattice can shift its optical absorption in the visible range. The size of the spherical nanoparticles was around 10-20 nm. Hence, Si-doped TiO2 prepared by ME method yields excellent and uniform features resulting in better performance for future applications.